1. Field of the Invention
This invention relates to polymeric compositions and films made from same. More specifically, this invention relates to the field of film products for fresh food packaging.
2. Background of the Invention
Synthetic polymeric materials, particularly polypropylene resins, are widely used in the manufacturing of a variety of end-use articles ranging from medical devices to food containers. Commercial grade polypropylenes are typically produced using either a Ziegler-Natta or metallocene catalyst mechanism in a polymerization process. Many industries, such as the packaging industry, utilize these polypropylene materials in various manufacturing processes to create a variety of finished goods.
Within the packaging industry, there are a number of unique applications that ideally require strong and substantially clear polymers. One such application is the manufacture of containers for the packaging of perishable food products. Fresh-cut foods, such as produce, respire or maintain an influx of oxygen and an efflux of carbon dioxide. Different types of fresh foods respire at different rates thus requiring different oxygen levels to maintain “freshness” or slow the aging process. Recent designs for packaging containers have attempted to modify the respiration rate of a food product by controlling the atmosphere within the packaging container. The atmosphere within the packaging container is determined by barrier properties of the container material such as permeability. Barrier properties refer to the permeability of the container material to gases and liquids such as oxygen and water. Such modified atmosphere packaging (MAP) containers have to strike a balance between the rates of gas and liquid exchange necessary to maintain food freshness with that necessary to minimize detrimental processes such as microbial growth. From a commercial vantage point, it is often necessary to also balance the mechanical properties of the polymeric material used to construct the MAP with the need for functionality and high quality aesthetics that are appealing to the consumer.
Given the foregoing discussion, it would be desirable to develop a polymeric material for food packaging applications having improved barrier properties. It would also be desirable to develop a polymeric material for food packaging applications having improved mechanical and optical properties.